Method of providing decorative coatings on wood products by tumbling



United Patent fiice 3,000,045 Patented Nov. 27, 1962 This invention relates to surface coated Wood products and methods of making the same. It is particularly applicable to Wooden handles for various implements, such as kitchenware, although it is not necessarily limited thereto and may be applicable to various other wooden products.

Handles for kitchen tools are commonly finished by the application of several liquid coatings made up of volatiles and non-volatiles which dry rapidly and leave a hard tough film when applied in thin coats. In accordance with commercially accepted processes, such articles have been finished by the application of a base film of sealer, over which a layer of undercoating, a layer of color coating and finally a coating of hard drying material, such as gloss lacquer, have been applied in succession and the finish obtained therefrom has proved durable, resistant to water and abrasion and yet sufficiently flexible to withstand the rigors of frequent washing and cleaning in mechanical as well as manual dish washing operations. However, the growing demand for finishes having a soft dull gloss and a worn look simulating the traditional, aged effects of antique finished cabinet woods, such for example as a fruitwood finish, has not been heretofore met inthe production of surface coatings on close-poredcheaper woods of the character used in relatively low priced kitchen tools and the like, such as birch and poplar.

It is accordingly an object of this invention to provide a process forimparting a hand-rubbed antique finish to the surface of wood articles, such as kitchen tool handles, which simulates the appearance of expensive or expensively treated cabinet Woods at a cost which renders it available for use on more abundant, inexpensive woods, particularly birch and poplar woods as used in volume production of relatively low priced kitchen tools.

In selecting woods for the production of handles of the type commonly used in the production of low priced kitchen tools, it is desirable to use materials which are free from odor, taste or staining and which are close grained and work well with industrial type surface conditioning equipment. Poplar or birch represent woods meeting these conditions and a surface coating exemplifying the present invention will, for convenience, be described as applied to handles of such woods.

Having thus selected a handle of wood, such as birch or poplar, and having obtained a smooth outer surface thereon by suitable commercial abrading processes, such for example as tumbling in pumice, the surface of the handle is ready for a base coating of sealer. Having se-. lected a sealer of suitable formulation and quality which is adapted for application by tumbling, a batch of such handles is placed in a revolving barrel containing the sealer. The sealer selected for this purpose is preferably pigmented to give a desired hiding power and may be a low viscosity solution coating based on any of the common vehicles used for wood sealers such as cellulosic resins, chlorinated rubber, shellac, polyvinyl butyral, or cold cut natural or synthetic resins or resin esters. The film former may be modified with plasticizing oils or chemical esters such as dibutyl phthalate, or alkyd resins.

A typical sealer example follows Parts by weight Nitrocellulose (dry) 5 Rosin acid ester 5 Toluol 2 Naptha 23 Ethyl acetate 23 Butyl acetate 13 Isopropyl alcohol 19 Weight per gal. l s 7.10 Viscosity cps use a slowly evaporating thinner which will permit the sealer to flow long enough so that a smooth coating results after rolling in the barrel for five minutes at room temperature.

the handles are allowed to dry while remaining in the barrel.

The smooth base sealer coating thus applied to the handles isnext supplanted by rough patches of an additional sealer coating dispersed over the area of the handle in a haphazard pattern. This action is carried out while.

the handles are subsequently revolved in the tumbling barrel in the presence of adidtional sealer coating of somewhat heavier viscosity than, that of the initial sealer coating. While so tumbled, the additional sealer is replenished from time to time until the handles commence to stick together in clusters, whereupon the tumbling is continued, Without replenishing the sealer coating, until the coating is dried. The second sealer coating thus solidifies in an uneven state to produce relatively thick patches of rough coating in random interspersed relation to areas having a relatively thin layer of such coating.

Having selected a desired color effect in the ultimate finished product, a stain close to such final color effect is next applied to the surface of the handles. The color coat consists of a solution of wood staining dyes in appropriate concentration to give desired shade. This dye solu tion may be modified with a wide variety of film forming materials such as cellulosic resins, shellac and other natural and synthetic resins. An example of a stain color coat is given below:

Parts by weight In accordance With a method which ofiers many advantages from the standpoint of producing coated handles in large quantities inexpensively-and rapidly, the stain as Well as subsequent coatings to be referred to hereafter After the handles have undergone such. action in the barrel, the sealer is drained therefrom andv 1:; are preferably applied by dipping the articles in a tank of the coating material. As an example of such method of production, a batch of handles, while supported in spaced apart relation on a supporting rack, are lowered into and lifted from an immersed position in a dip tank containing alcohol stain of desired color. in order to provide a desired film thickness, two coats of build lacquer colored with a shade of pigment corresponding to the color of the final color effect is thereafter applied by immersing the coated handles in a dip tank containing the build lacquer. The build coat finish is resin vehicle modified with plasticizer and/or resins, such as It must be understood that time is allowed to lapse for drying between successive coatings.

As each of the color coatings, namely the stain and the first and second build lacquer coatings is applied, the rough patches of sealer are still apparent in that such patches collect the coating material so as to become darker colored than the areas of smooth sealer coating surrounding said rough patches. Thus the surface of the handle as it appears after application of the stain and build lacquer coatings presents a mottled pattern of dark and light areas according to the pattern of the rough and smooth sealer coatings applied to the handle prior to such stain and build lacquer coatings. In handles of multi-sided shape, as distinguished from handles of completely convexly curved cross sectional contour, the edges of the handle sides also present light areas in contrast to dark areas on the surfaces bounded by said edges.

Having thus established a colored surface of dark and light areas, and after the second build lacquer coating has dried, the handles are next dipped in a high gloss film forming lacquer. The gloss lacquer when dried produces a very hard finish and thereby provides a good base for a subsequent and final coating of dull film forming lacuer. q In thus building up the thickness of the coating on the surface of the handle by the application of successive layers of lacquer, the dark and light colored areas undergo a dissolving action through the influence of the solvents contained in such lacquer coatings as well as the lacquer thinners with which said lacquers are mixed. This dissolving action serves to give the light colored areas a smooth, worn or aged appearance and simultaneously causes the dark areas to become feathered or graduated in color tone toward the light areas as well as to give the surface of such dark areas a smoothness blending with the surface of the light colored areas. Such blending of the dark and light areas in combination with the dull sheen obtained in the top coating of dull lacquer yields a finished product having protective qualities which will withstand handling and use as an article of utility in the day to day activity of a kitchen, and having decorative quality simulating the appearance of expensively treated woods, and in yielding such results the present invention makes use of materials and methods of application featuring economies in both time and cost compatible with volume production of relatively low priced merchandise.

It will be recognized by those versed in the art of coatings that the parti ular color may be varied as desired. As an example of color combination which adds to the artistic appearance of a handle surface having a surface coating embodying the features of this invention, fruitwood colored stain and maple colored build lacquer were selected as suitable color agents.

It will also be recognized that the formulation of the lacquers may also be varied in accordance with manufacturing procedures recognized as satisfactory in the industry. In other words, these lacquers can be prepared from the standpoint of viscosity, solvents, ratio of nitrocellulose to resins, and choice of resin so as to yield desirable characteristics as to flow, drying, resistance to moisture and durability. It will also be understood that the rate of speed which the article is removed from the coating material incident to each dipping operation is correlated with the consistency or rate of descent of the coating material to insure even and uniform application of the build" lacquer coatings and the finishing lacquer coatings.

What is claimed is:

1. In the manufacture of a wood product having a colored finish with a simulated, worn, aged look, the method comprising the steps of providing on the naked surface of said wood product an initial relatively even solidified coating of wood sealing liquid and thereafter tumbling a plurality of said wood products having such initial coating in a revolving barrel containing wood sealing liquid coating while adding wood sealing liquid of sufiiciently greater viscosity than that of the initial coating until the products commence to stick together and thereby producing relatively thick patches of uneven coating deposits in random interspersed relation over said initial evenly coated areas and continuing said tumbling action until said patches of uneven coating become dry and solidify in said state, subsequently applying a coating of body color on each of said products and applying in succession a series of lacquer coatings and drying each lacquer coating prior to the application of a succeeding lacquer coating, said lacquer coatings having a solvent content effective to reduce said patches of uneven coating deposits to a smoothness blending with the evenly coated areas and effective to cause the color of said patch portions to he graduated in color tone toward the color of said evenly coated areas.

2. In the manufacture of a wood product having a colored finish with a simulated, worn, aged look, the method according to claim 1 wherein said lacquers are applied by dipping said wood product in a solution of said lacquers.

References Cited in the file of this patent UNITED STATES PATENTS 625,979 Lynn May 30, 1899 1,147,066 Adler July 20, 1915 1,745,893 Ellis Feb. 4, 1930 1,857,161 Moss May 10, 1932 1,918,692 Fawkes July 18, 1933 1,927,086 Ellis Sept. 19, 1933 2,156,694 Johnson May 2, 1939 2,166,261 Moss July 18, 1939 2,324,098 Malm et a1. July 13, 1943 2,350,818 Rees June 6, 1944 2,734,831 Larsson Feb. 14, 1956 2,772,986 Buck Dec. 4, 1956 OTHER REFERENCES Newell: Coloring, Finishing and Painting Wood, Chas. A. Bennett Co., Inc., Publishers, Peoria, 111., pages 198-207 relied on, (1940).

Tumble Finishing of Small Wood Turnings, Wood Working Digest, March 1953, pages -93-102. 

1. IN THE MANUFACTURE OF A WOOD PRODUCT HAVING A COLORED FINISH WITH A SIMULATED, WORN, AGED LOOK, THE METHOD COMPRISING THE STEPS OF PROVIDING ON THE NAKED SURFACE OF SAID WOOD PRODUCT AN INITIAL RELATIVELY EVEN SOLIDIFIED COATING OF WOOD SEALING LIQUID AND THEREAFTER TUMBLING A PLURALITY OF SAID WOOD PRODUCTS HAVING SUCH INITIAL COATING IN A REVOLVING BARREL CONTAINING WOOD SEALING LIQUID COATING WHILE ADDING WOOD SEALING LIQUID OF UNTIL THE PRODUCTS COMMENCE TO STICK TOGETHER AND THEREBY PRODUCING RELATIVELY THICK PATCHES OF UNEVEN COATING DEPOSITS IN RANDOM INTERSPERSED RELATION OVER SAID INITAIAL EVENLY COATED AREASS AND CONTAINING SAID TUMBLING ACTION UNTIL SAID PATCHES OF UNEVEN COATING BECOME DRY AND SOLIDIFY IN SAID STATE, SUBSEQUENTLY APPLYING A COATING OF BODY COLOR ON EACH OF SAID PRODUCTS AND APPLYING IN SUCCESSION A SERIES OF LACQUER COATING AND DRYING EACH LACQUER COATING PRIOR TO THE APPLICATION OF A SSUCCEEDING LACQUER COATING, SAID LACQUER COATING HAVING A SOLVENT CONTENT EFFECTIVE TO REDUCE SAID PATCHES OF UNEVEN COATING DEPOSITS TO A SMOOTHNESS BLENDING WITH THE EVENLY COATED AREAS AND EFFECTIVE TO CAUSE THE COLOR OF SAID PATCH PORTIONS TO BE GRADUATED IN COLOR TONE TOWARD THE COLOR OF SAID EVENLY COAOTED AREAS. 